In many cases it is desirable to cool very hot particles without altering their chemical composition by oxidation as would occur if an ordinary fluidized bed were employed using a stream of air for fluidization and cooling. In such situations inert gas streams have been used as well as gas streams having reducing properties such as nitrogen and carbon monoxide respectively. Employing such gas streams is expensive since the gas must be recovered, cleaned and cooled before it is recirculated through the fluidized bed. Many improvements have been suggested for making such apparatus more economical as for instance by redesigning the distribution chamber and orifices below the fluidized bed. A considerable number of improvements have also been suggested for the recovery, cooling and recirculation of the cooling gases.
It is an object of this invention to provide simple means for cooling hot finely divided particles in a fluidized bed without effecting oxidation of the particles and more particularly to provide a means for cooling hot finely divided beneficiated and partially beneficiated ilmenite ore.